The present invention relates to a display device, and more particularly to a display device which includes thin film transistors (TFT) made of poly-silicon (poly-crystalline silicon).
As a kind of liquid crystal display device, conventionally, there has been known an active-matrix-type liquid crystal display device which includes an active element for every pixel, and operates the active element by switching.
As a kind of the active-matrix-type liquid crystal display device, there has been known a TFT-method active-matrix-type liquid crystal display module which uses a thin film transistor having a semiconductor layer made of poly-silicon (hereinafter, also referred to as a poly-silicon thin film transistor) as an active element.
In a liquid crystal display panel of the liquid crystal display module which uses the poly-silicon thin film transistor as the active element (hereinafter, referred to as a Poly-SiTr-TFT liquid crystal display module), the poly-silicon thin film transistors are arranged and formed on a quartz or a glass substrate in a matrix array. Further, an operation speed of the poly-silicon thin film transistor is higher than an operation speed of a thin film transistor having a semiconductor layer made of amorphous silicon. Accordingly, in the liquid crystal display panel of the Poly-SiTr-TFT liquid crystal display module, it is possible to form a peripheral circuit on the same substrate.